Kustomer API
Kustomer has a fully documented public REST API at developer.kustomer.com covering customers, conversations, messages, custom objects, and reporting. Auth is API keys or OAuth 2.0 for installable apps, with plan-tiered rate limits from 300 to 2,000 requests per minute.
Frequently asked questions
Kustomer scores A on the API Report Card. Kustomer has a fully documented public REST API at developer.kustomer.com covering customers, conversations, messages, custom objects, and reporting. Auth is API keys or OAuth 2.0 for installable apps, with plan-tiered rate limits from 300 to 2,000 requests per minute.
Kustomer has a workable official integration path. Most engineering teams can build against it directly. Open API: self-serve, documented, with SDKs
Kustomer is an AI-native customer service CRM that unifies customer interactions across email, chat, SMS, voice, social, and messaging apps into a single conversation-and-customer timeline.
Horizontal customer service / CX software with strong skew toward direct-to-consumer brands, marketplaces, on-demand delivery, travel, and fintech. Teams use Kustomer to (1) consolidate omnichannel conversations (email/chat/SMS/WhatsApp/IG/FB Messenger/voice) onto one customer timeline, (2) deflect contacts with AI Agents and KB self-service, (3) route and triage with workflow/business rules and queues, (4) give agents a 360 view enriched with Shopify orders, Klaviyo segments, shipping events, and loyalty data, and (5) report on CSAT, resolution times, and agent productivity.
Moderate. Kustomer reports ~600 customers, much smaller than Zendesk (100k+) or Freshdesk (74k+), but with disproportionate brand recognition among DTC/e-commerce CX teams thanks to high-profile logos and the Meta acquisition.
For any consumer brand, the Kustomer API is the operational heartbeat of customer experience: every conversation across every channel, every message body, every customer record with attached orders/shipments/loyalty data, every KObject (custom object) carrying business-specific data, agent activity, queues, SLAs, satisfaction surveys, and KB content.
Founded in 2015 in New York by Brad Birnbaum and Jeremy Suriel (both ex-Assistly/Desk.com). Acquired by Meta in early 2022 for ~$1B, then spun back out as an independent company in late 2023 with backing from Battery Ventures.
Grades measure one thing: can a customer's engineering team get their own data out programmatically? We check six things (whether a real API exists, how access is gated, data coverage, auth quality, docs and developer experience, and stability) and roll them into a letter grade. Grades get re-verified, and they only move on evidence.